Braking means for automobile vehicles.



A. KREBS.

BRAKING- MEANS FOR AUTOMOBILE VEHICLES.

APPLICATION FILED FEB. 15, 1908.

Patented Sept. 21, 1909.

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A. KREBS. BRAKING MEANS FOR AUTOMOBILE VEHICLES. APPLICATION FILEDFEB.15, 190a.

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ARTHWFYKREBS,

ARTHUR KREBS, 0F PARIS,

FRANCE, ASSIGNGR TO LA SOCIETE ANONYME DES ANCIENS ETABLISSEMENTSPANHAED 1T1 LEVASSOBJ, 0F PARIS, FRANCE.

BRAKING MEANS F613, AUTOMOBILE VEHICLES.

Specification of Letters Patent.

Patented Sept. 21, 1909.

Application filed February 15, 1908. Serial No. 416,086.

T 0 all whom it may concern:

lie it known that I, ARTHUR Knees, a citizen of the Republic of France,and resident of Paris, France, have invented new and useful improvementsin and Relating to Braking Means for Automobile Vehicles, whichimprovements are fully set forth in the following specification.

The present invention has for its object a means for effecting thebraking of an automobile vehicle by converting the driving effort into aresistant effort.

\V hen a four-phase motor is running, if the suction pipe beol'iturated, the two phasessuction and compression-will balance eachother as efforts and will not give rise to any resistant effort apartfrom passive resistances. The two following phases, corresponding to theexplosion followed by expansion and to the exhaust, give rise to aresistant efiort resulting from the partial vacuum produced by thedescent of the piston, Which vacuum is filled as soon as the pistonrises again by the establishment of atmospheric pressure at the momentat which the exhaust valve is opened. This arrangement, which has beenindicated in a prior patent dated the 9th. July 1900 No. 302027,- provesto be a very real braking effort but one which is generally speakinginsufiicient. In order to increase it, itis preferable to resort to anarrangement which consists in providing two additional cams A and 13upon the exhaust cam shaft; these two cams are arranged as shown inFigure 1 of the accompanying drawing, relatively to the exhaust cam C.The two cams A and B become operative owing to the longitudinaldisplacement, along its axis, of the exhaust cam shaft, the angularposition of this cam shaft relatively to the crank shaft not beingmodified.

The object of the cam A is to lift the ex haust valve at the moment atwhich the piston reaches the end of the suction period and to close itsubsequently when the piston has begun to ascend for the compressionperiod.

The cam B serves for lifting the exhaust valve at the moment at whichthe piston reaches the end of the compression period and to close itwhen the piston has passed beyond the upper dead point and the expansionperiod begins.

In order to apply braking, communication with the carbureter iscompletely out off and the exhaust cam shaft is displaced longitudinallyso as to cause the additional cams A and B to pass beneath the roller 1)of the rod j for lifting the exhaust valve (Fig. :2). Taking the pistonat the moment at which, when at the top of its stroke, it is about tobegin the suction period or first phase T (Fig. 1). During this period,as communication with the carbureter is cut off, a partial vacuum isestablished above the piston and creates a certain resistance R duringthis first phase. When it has reached the end of its travel the cam Alifts the exhaust valve during the passage of the bottom dead point, andthrough this valve inert gases enter the cylinder and fill it. When thepiston again ascends, that is to say at the second phase T as soon asthe exhaust valve is closed, the piston has to overcome the work ofcompressing the gases introduced, so that it experiences a secondresistance R At the end of this compression stroke, the cam B lifts theexhaust valve through which the compressed gases escape and then closesit at the moment at which the piston descends for the third or expansionphase T These compressed gases being expelled and communication with theexterior being still cut off, a partial vacuum is established as at thefirst phase and opposes a third resistance R to the movement of thepiston. When the piston has reached the bottom of its stroke the exhaustvalve opens normally under the in fiuence of the ordinary cam andenables the gases contained in the exhaust pipe to fill the voidproduced above the piston. WVhen the piston again ascends, that is tosay at the fourth phase T, the piston is not acted upon by any forcetending to raise and force in frontof it, through the open exhaustvalve, the gases which have entered the cylinder. The succession of thephenomena which have just been analyzed therefore, during foursemi-revolutions of the crank, produce im portant resistance duringthree semi-revolutions in addition to the ordinary passive resistances.Experience has demonstrated that the resistant work of a motoroperatingin this manner is greater by fifty per cent. than the motoreffort of the same motor acting at its full power.

The longitudinal displacement of the exhaust cam shaft for the purposeof bringing it into the operative conditions described above may beobtained in various ways. In Fig. 3 a method is shown which consists inproviding on the extremity of the cam shaft a sleeve (6 controlled by alever b pivoted at 0. At its other extremity d, this lever is providedwith a rod 6 connected with the bent pedal lever springs keep the pedalsraised so that the cam shaft remains in the proper position forpreventing the additional cams from lifting the exhaust valves. If,however, the pedal be depre sed, the c m shaf i d p ac d, to- Ward he font and the additional am com into the plane of the roller of the rodfor lifting each of the exhaust valves. At the same time, communicationwith the carbureter may be out off by means of an appropriate device, ifit has not been closed otherwise.

Having now particularly described and f. In the normal positionascertained the nature of my said invention and in what manner the sameis to be performed, I declare that what I claim is 1. The combination,with an explosive engine, of a camshaft, an exhaust cam and twoadditional ca ms attached to the exhaust cam shaft, the two additionalcams being so spaced circumferentially that they will produce within theengine cylinder three resistant phases to the motor piston whereby inthe body of the cylinder itself a greatly increased braking action isobtained.

2. In a four cycle explosive engine, in combination an exhaust cam, twoadditional cams mounted in the same plane with the exhaust 0am, and alongitudinally displaceable exhaust cam shaft, adapted to produce atpredetern'iined interw 'als three resistant per ods in the four cycles.

In testimony whereof I have signed this specification in'the presence oftwo subscribing witnesses.

ARTHUR KREB S.

H. C, C'oxm.

